For long marathon-training runs, plan carbohydrate intake rather than relying on a sparkling energy drink as your fuel; a carbohydrate sports drink, gels or food can contribute to that plan. A fizzy energy drink is a separate caffeine choice for an adult who has checked their total intake and tried the drink during training. Sugar-free versions do not provide carbohydrate from the drink.
For runs lasting around 1–2.5 hours or longer, the question is how a drink fits your carbohydrate plan. World Athletics describes carbohydrate drinks, gels and confectionery as possible ways to take in carbohydrate during endurance events.
If caffeine is the reason for choosing an energy drink, check the amount in the whole container alongside coffee, gels and other sources. Try the intended drink and serving size during training rather than for the first time on race day.
A sugar-free sparkling drink can meet a preference for that style of drink, but it is not a substitute for carbohydrate that you planned to obtain from a sports drink. Check how the rest of your long-run fuelling plan supplies it.
Choose it when: You want some of your planned carbohydrate and fluid from the same drink during a long run.
Bear in mind: It contributes carbohydrate, so account for it alongside gels or food; it need not be part of every short run.
Choose it when: As an adult, you want a separately planned caffeine drink and have already tried it during training.
Bear in mind: A caffeinated soft drink is not, by itself, a plan for carbohydrate and fluid over a marathon.
| Priority | What to check | Your needs |
|---|---|---|
| Carbohydrate plan | Check carbohydrate per serving and how much you intend to drink each hour. World Athletics lists 30–60 g per hour for events lasting 1–2.5 hours and up to 90 g per hour for events longer than 2.5 hours; drinks can be combined with other carbohydrate sources. | I want to know how much of my long-run fuel comes from the drink, rather than treating the word “energy” as a measure of carbohydrate. |
| Caffeine amount | Read caffeine per full can or bottle and include other sources consumed that day. The European Food Safety Authority’s 2015 assessment found no safety concern for the general healthy adult population at single doses up to 200 mg or daily intake from all sources up to 400 mg; these are not performance targets. | If I choose caffeine before a run, I need to account for coffee, gels and other caffeinated products as well as the drink. |
| Sugar-free choice | Check the nutrition panel for carbohydrate, not just a sugar-free description. Monster Energy UK lists 0 g sugar per 500 ml for Monster Ultra, while Red Bull UK says its sugar-free drinks replace sugars with non-caloric sweeteners. | A sugar-free fizzy drink suits my preference only if I am getting any carbohydrate needed for the run elsewhere. |
| Fizz and serving size | Check whether the drink is carbonated, the container volume and the amount you plan to drink while running. Practise the same serving and timing in training; research on carbonated drinks does not establish how every marathon runner will tolerate them. | I would rather find out during training whether the fizz and drinking volume are comfortable at my running pace. |
An energy drink and a carbohydrate sports drink serve different purposes. World Athletics bases longer-event fuelling guidance on carbohydrate intake, which a product name alone cannot tell you.
Work out how much carbohydrate your drink, gels or food will contribute during the run before considering caffeine separately.
Monster Energy UK lists 0 g sugar per 500 ml for Monster Ultra. Choosing a sugar-free drink does not provide the drink-based carbohydrate that a long-run plan may call for.
If you want the sugar-free drink, plan and practise a separate carbohydrate source, or compare carbohydrate sports drinks instead.
Monster Energy UK lists 160 mg caffeine in a 500 ml Original Green can. The European Food Safety Authority’s adult assessment concerns caffeine from all sources, not each drink in isolation.
Add up caffeine from drinks, coffee, gels and other products. If pregnant, follow the NHS advice to have no more than 200 mg caffeine a day.
How a carbonated drink feels during a run can differ from drinking it at rest. Research on carbonated drinks has limits when applied to individual marathon runners.
Try the intended drink, volume and timing on a comparable training run; choose a non-carbonated option if the fizz does not suit you.
These references describe relevant drink ranges and retailer categories; they do not indicate which products a retailer currently has in stock.
Lucozade Sport is a carbohydrate sports-drink option, distinct from the brand’s Lucozade Energy range.
A sparkling energy-drink range that includes original and sugar-free choices.
Sparkling energy drinks with different sugar and caffeine amounts across the Original Green and Ultra variants.
A sparkling energy-drink brand rather than a specified marathon sports-drink formulation.
A retailer whose drink categories distinguish sports drinks from energy drinks.
A retailer named on Relentless’s retailer page.
These options include a Lucozade Sport multipack for drink-based carbohydrate planning and energy drinks to consider separately when comparing fizzy or caffeinated choices.
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Consider this sports-drink multipack if you want to include drink-based carbohydrate in a long-run plan. Tesco lists approximately 16 g carbohydrate per 250 ml for its Lucozade Sport Orange 500 ml bottle; check the multipack label and practise the amount you intend to drink. Check carbonation separately if fizz matters to you.
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This is a carbonated energy-drink choice to consider separately from a marathon fuelling plan. The Joybuy product description identifies a 12-pack of 250 ml cans containing sugars; check the can’s caffeine amount and count other caffeine sources before use.
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Compare this Energy variant with Lucozade Sport by checking what each bottle contributes to your intended run-day plan. Check the 380 ml bottle’s carbohydrate, caffeine and carbonation information rather than assuming it has the same formulation as the sports drink.
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If considering this 500 ml energy drink for a training day, compare the caffeine in a full can with everything else you expect to consume. Check its nutrition panel against your carbohydrate plan, and try the intended serving during training rather than on race day.
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Consider the 355 ml can as a separate drink choice, not a substitute for calculating long-run carbohydrate intake. Check its current label for carbohydrate, caffeine and carbonation, and practise your intended drink strategy in training.
No. The American College of Sports Medicine distinguishes energy drinks from sports drinks. For longer endurance events, World Athletics lists 30–60 g carbohydrate per hour for 1–2.5 hours and up to 90 g per hour beyond 2.5 hours. A carbohydrate sports drink can contribute to that plan; a caffeinated energy drink should not be treated as the whole strategy.
Not as a source of carbohydrate from the drink. Monster Energy UK lists 0 g sugar per 500 ml for Monster Ultra, and Red Bull UK says its sugar-free drinks replace sugars with non-caloric sweeteners. If you choose one, plan any carbohydrate needed for the run from another drink, gels or food, and practise that combination in training.
Count caffeine from the full drink and from coffee, gels and other sources consumed that day. The European Food Safety Authority’s 2015 assessment found no safety concern for the general healthy adult population at single doses up to 200 mg and daily intake from all sources up to 400 mg; those figures are not a running-performance recommendation. The NHS advises no more than 200 mg caffeine a day during pregnancy.
Try it on a comparable training run instead. The UK Sports Institute notes that what works before a run varies considerably between individuals, and research on carbonated drinks does not establish how a particular runner will tolerate a given serving. Practise the same drink, amount and timing you intend to use.
Do not assume there is a single UK-wide rule on that basis. In its July 2026 announcement, the UK Government said a ban on sales to under-16s in England of drinks other than tea or coffee containing more than 150 mg caffeine per litre was intended from April 2027, subject to Parliamentary approval. That announcement does not establish a current restriction across Scotland, Wales or Northern Ireland.